The greatest threat to democracy is not from external enemies but from internal decay and the loss of civic virtue.
对民主的最大威胁不是来自外部敌人,而是来自内部腐败和公民美德的丧失。
The power of mathematics lies in its ability to simplify the complex.
You may have the worst of your worries when you most appear to be at ease.
 一个词的意义不是心智实体,而是社会实践。